DESCRIPTION: Optimal nutritional management for children with cystic fibrosis (CF) is critical for growth, quality of life, and long-term health outcomes. Diagnosis of CF typically occurs between age 6 and 18 months, and one of the first treatment priorities is to get the toddler with CF to eat 50 percent more than an average toddler typically eats. Research is needed to better understand how toddlers with CF (ages 12-36 months) and their families are meeting this biobehavioral challenge because parent-child mealtime interactions learned at this developmental period set the stage for appropriate eating behavior in the future and most older children with CF are not meeting the CF nutritional goals. Two studies will be conducted. Study 1 will identify the mealtime behaviors of toddlers with CF and their parents and compare these behaviors with age-matched, non-chronically ill toddlers and their parents. Study 2 will use the information from Study 1 to develop and test the efficacy of an empirically- derived behavioral parent-training intervention designed to prevent and/or treat eating behavior problems and enhance growth and development in this population. A prospective, cross- sectional design comparing 30 toddlers with CF and 30 non-chronically ill toddlers will be used in Study 1. A randomized clinical trial design comparing 20 toddlers with CF randomly assigned to a behavioral parent-training intervention (n=10) or an enhanced standard medical care intervention (n=10) will be used in Study 2. For both studies, data will be obtained on child and parent mealtime behaviors, mealtime duration, calorie intake, parent perceptions of mealtimes, and weight. For Study 1 it is hypothesized that toddlers with CF and their families will exhibit more mealtime behavior problems than non-chronically ill toddlers and their families. Data from Study 1 will describe the specific eating problems exhibited by toddlers with CF. For Study 2 it is hypothesized that the behavioral intervention will result in significantly more improvement on behavioral variables such as toddler and parent mealtime behavior, greater calorie intake, and weight gain than the enhanced standard medical care intervention. The long-term objective of this programmatic research plan is to prevent and/or treat the early development of eating behavior problems for children with CF, and therefore decrease the morbidity and mortality associated with malnutrition in CF.